Department of Infectious Diseases and Clinical Microbiology, Cerrahpaşa Medical Faculty, Istanbul University-Cerrahpaşa, Istanbul, 34098, Turkey.
Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Bezmialem Vakıf University, Istanbul, 34093, Turkey.
Ir J Med Sci. 2023 Feb;192(1):19-25. doi: 10.1007/s11845-022-02984-1. Epub 2022 Mar 28.
Despite high vaccination rates, increasing case numbers continue to be reported with the identification of new variants of concern, and the issue of durability of the vaccine-induced immune response remains hot topic. Real-life data regarding time-dependent immunogenicity of inactivated COVID-19 vaccines are scarce. We aimed to investigate the changes in the antibody at the different times after the second dose of the CoronaVac vaccine.
The study included 175 HCWs vaccinated with inactive CoronaVac (Sinovac Life Sciences, China) SARS-CoV-2 vaccine in two doses. Anti-spike/RBD IgG levels were measured first, third, and sixth months after the second dose. Chemiluminescent microparticle immunoassay (IgG II Quant test, Abbott, USA), which is 100% compatible with plaque reduction neutralization test, was used.
Mean age of the participants was 38 ± 11.23 years (range between 22 and 66) of whom 119 (63.9%) were female, and 56 (32%) were male. Dramatic reductions were demonstrated in median antibody levels particularly in the infection-naïve group, comprising 138 HCWs compared to those with prior history of COVID-19 infection (n = 37) (p < 0.001). There was no difference between the two groups in terms of age, gender, blood groups, BMI, and comorbid diseases.
While antibody positivity remained above 90% in the 6th month after two doses of inactivated vaccine in HCWs, the median titers of neutralizing antibodies decreased rapidly. The decrease was more rapid and significant in those with no history of prior COVID-19 infection. In this critical phase of the pandemic, where we are facing the dominance of the Omicron variant after Delta, booster doses have become vital.
尽管疫苗接种率很高，但随着新关注变种的出现，病例数量仍在不断增加，疫苗诱导的免疫反应持久性问题仍然是热门话题。关于灭活 COVID-19 疫苗免疫原性随时间变化的真实数据仍然缺乏。本研究旨在研究科兴（Sinovac Life Sciences，中国）灭活 SARS-CoV-2 疫苗（CoronaVac）第二剂后不同时间的抗体变化。
该研究纳入了 175 名接种两剂灭活科兴疫苗（CoronaVac）的医护人员。在第二剂后第 1、3、6 个月测量抗刺突/RBD IgG 水平。采用化学发光微粒子免疫分析（IgG II Quant 测试，美国雅培），该方法与噬斑减少中和试验 100%兼容。
参与者的平均年龄为 38 ± 11.23 岁（范围为 22 至 66 岁），其中 119 名（63.9%）为女性，56 名（32%）为男性。与先前有 COVID-19 感染史的 37 名参与者（n=37）相比，138 名无感染史的医护人员（感染-naive 组）的抗体水平中位数显著下降（p<0.001）。两组在年龄、性别、血型、BMI 和合并症方面无差异。
在接种两剂灭活疫苗后第 6 个月，医护人员的抗体阳性率仍保持在 90%以上，但中和抗体的中位数滴度迅速下降。在无先前 COVID-19 感染史的人群中，下降更为迅速和显著。在大流行的这个关键阶段，我们面临着 Delta 之后的奥密克戎变种的主导地位，加强剂已变得至关重要。
